Obesity is an increasing health problem all over the world. In addition to genetic and many environmental factors, television is also thought to be a risk factor. This study examined the effects of television viewing on obesity and other physical complaints among Turkish children. From two different socioeconomic class primary schools, 886 second- and third-grade children were visited at their schools, and their weight, height and triceps skin fold thickness (TST) were measured and body mass index (BMI) calculated. Television viewing behavior of the children, parental weight and height, and physical complaints of children were investigated by a questionnaire sent to parents. A subgroup of children was also called to the hospital, and their blood lipid profile and visual acuity were measured. According to the questionnaires, children were found to watch television 2.1 +/- 1.2 hours/day (hr/d) during the weekdays, 3.4 +/- 2.1 hr/d at the weekend and 2.5 +/- 1.3 hr/d generally. Children were also grouped according to the amount of time they watch television. Group 1 (n = 298) children watched television less than 2 hr/d, Group 2 (n = 323) watched 2-4 hr/d, and Group 3 (n = 68) more than 4 hr/d. The prevalence of obesity was 10.9% according to BMI, 11.8% according to TST and 6.4% according to both criteria. Obese girls were found to watch television longer than their peers (2.9 +/- 1.2 hr/d vs 2.3 +/- 1.3 hr/d, respectively, p = 0.034), but no other relation was found between television viewing and obesity. Headache, back pain, eye symptoms and sleep problems were found to be more often among children who watched television longer (p < 0.05). It was concluded that television viewing is related to many physical complaints, which may have lifelong consequences (obesity). Thus, pediatricians should give appropriate guidance to families about television habits and health consequences.